The invention relates to a medical gripping instrument for use with endoscopes.
Known instruments of this type generally have at least two parallel ducts or channels in a common endoscope shaft which envelopes the same. One of the two ducts contains the periscope or viewing tube, whilst the other duct arranged eccentrically to the complete endoscope shaft contains a sleeve containing the resilient gripping arms. By means of the rods at the proximal end of the endoscope, said arms can be displaced with respect to the sleeve, so that they are moved out of the latter to the front and extend laterally with respect to the said sleeve. Generally, there are three such gripping arms, which are drawn back into the sleeve by a spring at the proximal end and are consequently returned to their closed position. This firstly leads to the disadvantage that the gripping arms are arranged eccentrically to the periscope, so that when operated in the vicinity of the distal end, they cannot be seen or can only be partly seen through the periscope. Another disadvantage results from the fact that the endoscope shaft as a whole must be relatively thick, because it has to receive at least the two parallel ducts.
In addition, an endoscope with a longitudinally displaceable wire loop is known, in which the connection of the telescopic periscope with the loop takes place by means of a gear in such a way that the periscope is displaced less than the wire loop. This permits the use of a telescopic periscope with a wide field of view, substantially without impeding vision through the edge of the endoscope shaft (Germany DOS No. 2,628,555).